[PATCH] Fix "-mno-global-merge" option for clang

[Bob Wilson]

> On Jul 25, 2014, at 4:47 PM, Steven Wu <stevenwu at apple.com> wrote:
> 
> This patch fixes the problem in clang after llvm changes the option for global-merge in r210639. When using “-mno-global-merge”, clang will return following error currently:
> clang: Unknown command line argument '-global-merge=false'.  Try: 'clang -help'
> clang: Did you mean '-enable-global-merge=false’?
> This patch should fix this problem.
> 
> I try to add a test case but it is not very obvious because there are no current examples for backend options. I add two tests in mno-global-merge.c to make sure it actually runs. If anyone has better idea how to handle this, please let me know.
> 
> I don’t have permission to commit the patch. Please help me to commit after review.

LGTM. I committed it for you in r213993.